The present invention relates to folding handrails which are adapted for use with telescoping seating systems. Folding or telescoping handrails of this type are disclosed in U.S. Pat. No. 3,401,918 of Harold Wiese for "Foldable Handrail", and improvements are described in the co-owned application Ser. No. 550,478, filed Feb. 18, 1975, now U.S. Pat. No. 3,964,215 for "Improvements in Folding Handrails for Telescoping Seating Sections", of Hartman and Vance.
In telescoping seating systems of the type with which the present invention is concerned, the seating system is made from a number of individual row sections which are adapted to move relative to each other so that a lower row section telescopes beneath an upper row section when the system is retracted for storage. For use, the row sections are extended outwardly, and when fully opened, they are in stepped relation.
Prior to the systems disclosed in the above-referenced patent and application, most handrails for telescoping seating systems had to be removed prior to retraction, and after removal, the handrails were stored on the tread panels in the row sections. Such systems required the use of maintenance personnel to install handrails prior to use and to remove them prior to retraction of the seating system. Because it was necessary to mount the rails in such a way that they could not easily be tampered with or removed by occupants, such as students, the amount of time required to mount and remove the rail sections resulted in infrequent use of the rails. Typically, the handrails would be stored in a location apart from the seating system, and not always assembled when the seating system was extended for use. More recently, systems have been designed wherein the rail sections are secured permanentaly to the row sections and need not be removed when the seating system is retracted.
These latter systems employ a series of telescoping tubes to form an extensible rail assembly. If these rail assemblies have their lowermost tubes pivotally connected to a lower post and their uppermost tubes pivotally connected to an upper post, both posts being mounted to seating rows, the rail assemblies are designed for a particular rise and span. That is, the number of tubular elements and their length is determined by the rise and span of the system. The rise of a seating system normally refers to the height of each individual row; and the span normally refers to the row-to-row horizontal spacing in the extended position.
When referring to handrails and realizing that the posts may be spaced two or three rows apart, the vertical distance between corresponding points adjacent posts is referred to as accumulated rise, and the horizontal spacing between corresponding points on adjacent posts when the system is extended is referred to as accumulated span.
Prior rail assemblies cannot be adapted to seating systems of substantially different rise or span than those for which they were originally designed. When it is realized that rise and span may differ for different installations, may even vary within a given installation and certainly differ for different types of seating (for example, bleacher vs. folding chair), the problem will be understood.
The lack of versatility of a given handrail design is further accentuated because the handrail extends between two posts in the extended position; and, therefore, these connections act as a restraint in the folded or retracted position.
In a folding handrail, it is desirable to use, as the handrail assembly, a plurality of telescoping tubular elements. In theory, such an assembly may be telescoped to the length of a single elememt, and in the extended position, it may span an overall dimension equal to the number of individual tubular elements times the length of one element. However, in order to provide structural integrity, there is a need for some overlap between adjacent tubular elements. Hence, the effective extension for each individual tubular element is reduced by 20-25% (i.e., the actual length less the overlap). For long accumulated spans, it may seem a simple expedient to add more tubular elements to the handrail assembly, but this has two drawbacks (1) the number of elements for a short accumulated rise becomes excessive, and (2) the variation in diameter along a rail assembly becomes uncomfortable to the hand of a user. There are other disadvantages such as the lack of esthetic appeal, and the impracticality of manufacturing tubular elements of a large number of diameters.
In summary, telescoping handrail assemblies have had to be specially dimensioned for a given accumulated rise and accumulated span, and it has been difficult to adapt such assemblies to platform seating systems where the accumulated rise is relatively small.
In the present invention, a plurality of telescoping tubular elements form a rail assembly which is pivotally connected at its lower end to one post on the seating system. A sleeve is slidably received on the uppermost tubular element, and a link pivotally interconnects the sleeve with the upper post.
The uppermost tubular element of the rail assembly is provided with an upper peripheral stop ring and a lower peripheral stop ring. The upper ring engages the sleeve during extension of the seating system and holds it adjacent the pivotal connection to the upper post so that the rail assembly may be extended as the seating system is opened. The lower stop ring engages the lower portion of the sleeve when the seating system is closed, and this forces the rail assembly to its retracted position during storage.
An adjustable stop member is also provided on the link for engaging the associated post during extension of the system when the link is in proper alignment with its associated rail assembly. This insures that when the system is fully opened, all of the tubular elements are axially aligned, both for upper and lower rail assemblies.
With the present invention, then, when the seating system is closed, the rail assembly is telescoped to its shortened position, and the sleeve slides downwardly on the uppermost tubular element. This permits the rail assembly, in the closed position, to extend a distance which is greater than the distance between the pivotal connections of the rail assembly to its associated posts. That is to say, with the present invention, the retracted length is not limited to the accumulated rise between adjacent posts since the upper end of a rail assembly swings upwardly in the retracted position. The present invention accommodates longer tubular elements, and hence a fewer number, for a given accumulated span. With the present invention, the same handrail assembly can be used on seating systems with different rises. Because of the telescoping characteristic of the handrail assembly, it automatically accommodates to seating systems with different accumulated spans.
Further, by slanting the posts forwardly, the rail assemblies assume an upright position and storage. By mounting both the link and the lower tubular element of an upper rail assembly to a common pin, upper and lower rail assemblies may be used, and they will be aligned in the same vertical plane for all positions. This is desirable from both a functional and an esthetic viewpoint.
Other features and advantages of the present invention will be apparent from the following detailed description of a preferred embodiment accompanied by the attached drawing wherein identical reference numerals will refer to like parts in the various views.